Apparatus for interrupting the flow of mercury and/or of amalgam in electrolytic cells



June 6. 1967 P. DRUYLANTS 3,324,020

APPARATUS FOR INTERRUPTING THE FLOW OF MERCURY AND/OR OF AMALGAM IN ELECTROLYTIC CELLS Filed July 16, 1963 I 3 Sheets-Sheet 1 FROM cATHoos SEPARATOR FIG.I.

INVENT OR Fl 6 2 r PuuI Druylants BYW W ATTORNEYS June 6. 1967 v P. DRUYLANTS 3, ,0

APPARATUS FOR INTERRUPTING THE FLOW OF MERCURY AND/OR OF AMALGAM IN ELECTROLYTIC CELLS 'Filed July 16, 1963 a Sheets-Sheet 2 FIG.3CI.

INVENTOR Poul Druylcnts ATTORNEYS Jun 6. 1967 P. DRUYVLANTS Filed July 16, 1963 APPARATUS FOR INTERRUPTING THE FLOW 0F MERCURY AND/OR 0F AMALGAM IN ELECTROLYTIC CELLS 5 Sheets-Sheet 5 l6 9 {Q Is 5 8 p S 2 E 20 2o l2 24 I5 4 INVENTOR Poul Druylunts FIG.5. BY Z ATTORNEYS United States Patent APPARATUS FOR INTERRUFTING THE FLOW OF MERCURY AND/0R OF AMAL'GAM IN ELEC- TROLYTIC CELLS Paul Druylants, Woluwe-Saint-Pierre, Brussels, Belgium,

assignor to Solvay & Cie, Brussels, Belgium Filed July 16, 1963, Ser. No. 295,548 Claims priority, application Netherlands, July 20, 1962, 281,239 Claims. (Cl. 204-219) The present invention relates to an apparatus for interrupting the flow of mercury and/ or amalgam through the inlets and/or outlets of cells with liquid mercury cathodes for the electrolysis of aqueous solutions of alkali metal halides.

It is known that a flowing of the liquid mercury cathode of such a cell causes a diversion of the electrolysis current, especially toward the amalgam decomposer. Various methods have been suggested for avoiding appreciable losses of energy resulting from such current diversion.

It has therefore been suggested in French Patent 503,- 288 to reduce considerably the cross sectional area of the flow channel of the mercury by the employment of the tubes of small diameter so as to reduce the diverted current. It has also been suggested to pulverize the mercury to increase its electric resistance, such pulverization being effected by vibration of a column of mercury, by its fall upon a wheel rotating at high speed, with the action of compressed air, by a magnetic field, or by high voltage electricity.

The discontinuity of the flow of mercury can also be effected by closing and opening of a valve controlled by a shaftwith cams on it, by compressed air, or by an electromagnet (French Patent 503,288, US. Patent 2,849,- 524).

In the German Patent 838,118 it is suggested that the flow be interrupted by successively starting and stopping a siphon, while according to the Belgian Patent 482,217 a jet of mercury is broken by means of cup carriers or bladed Wheels.

All of these devices are inconvenient in being complicated and uncertain in their operation. That is why it has been suggested in US. Patent 2,849,524 to use a horizontal rotating drum divided into cylindrical compartments by vertical closures each provided with an open sector which puts each compartment into electric contact, sometimes with the one behind it, and sometimes with the one ahead of it. Although such a device will avoid the above mentioned difiiculties, it still requires the presence of an insulating lining to insulate the compartments from one another. Furthermore, it requires careful regulation, and during rotation of the drum the compartments cannot be entirely emptied of mercury or of amalgam.

The object of this invention is to provide an apparatus which avoids the above difficulties. It presents no manufacturing difficulties since there are no internal partitions or fixtures inside of cylinders.

According to one aspect of the present invention in a preferred embodiment thereof, it is suggested to provide for the following arrangement: In a housing there are disposed a plurality of coaxial drums. These drums are either completely electrically insulated from each other, or, if integral, at least the liquid receiving space of each drum is provided with an insulated lining; in any event, the liquid receiving space of each drum is electrically insulated from the corresponding liquid receiving space of any other drum. Each drum is provided with a discharge outlet and the discharge outlets of the several drums are angularly displaced around the common "Ice axis to such an extent, that liquid can be discharged only from one drum at a time. Proper degassing and liquid discharge means are provided in the housing, and conduit means run insulatedly into the innermost drum for discharging mercury or amalgam or both into this innermost drum.

While the specification concludes with claims 'particu-' larly pointing out and distinctly claiming the subject matter which is regarded as the invention, it is believed that the invention, the objects, and features of the invention and further objects, features and advantages thereof will be better understood from the following description taken in connection with the accompanying drawing in which:

FIGURE 1 is a longitudinal section of a first embodiment of the invention;

FIGURE 2 is a transverse section on the line A-A of FIGURE 1;

FIGURES 3a, 3b, 3c and 3d are transverse sections showing the cylinders in their various positions to show the manner of functioning, and

FIGURES 4 and 5 show modifications of the first embodiment and in longitudinal cross sectional view,

As is shown in FIGURE 1, the apparatus of this eX- ample of the preferred embodiment of the invention is comprised of two coaxial cylinders or drums 1 and 2 rotating in a stationary housing 3 that is electrically insulated from the cylinders or drums 1 and 2. Drums 1 and 2 respectively have hollow axial extensions 4, 4' and 5, 5' which are also insulated from each other but which journal the drums in the housing 3. 6, 6 and 7, '7 are roller bearings in which the hollow shafts 4, 4 and 5, 5' are mounted respectively for rotation. These extensions are secured to each other by a coupling system 8 having insulating rod 10 to keep the drums insulated from each other. Both of these cylinders are driven in unison by the motor 9 which can be mounted either outside or even inside the housing 3. Power transmission from motor 9' to drums 1 and 2 can be had by any known means, such' insulated therefrom there are provided conduits 12 and 13 for delivering mercury and pure water respectively into the innermost drum which is cylinder 1. Although the use of water is not absolutely necessary, it is advantageous in assisting the mercury to collect instead of clinging to the walls.

Each of these drums 1 and 2 is pierced by at least one longitudinal opening 14 and 15 respectively and each extending preferably the entire length of the respective cylindrical mantle of the drum, the openings in the twodrums are displaced from each other by half the angle between successive openings. It is generally sufiicient to use a minimum number of openings and in the apparatus here shown there is only one opening per drum. The two openings 14 and 15 are therefore diametrically opposite each other and permit the passage of mercury and/or amalgam (and water) by gravity, first from drum 1 to drum 2 and then from drum 2 to drum 3, the flow of mercury being thus interrupted alternately between drum 1 and drum 2 and between drum 2 and drum 3. Furthermore, by reason of the relative angular positions of the openings 14 and 15 around the common axis of rotation, the drums 1 and 2 are emptied alternately of all the mercury and/ or amalgam which they contain, but emptying or drum discharge does never occur simultaneously for all drums. V

The housing 3 is provided with an outlet 17 for the discharge of mercury and/ or amalgam and water. It is also provided with baffles 18 to prevent water from getting to the various bearings. Finally, a degassing outlet 16 is provided on top of housing 3.

FIGURES 3a, 3b, and 3d represent different operating stages of the apparatus described thus far. The direction of common rotation of the several drums is represented by the arrow. I

In FIGURE 3a the mercury and the water are being led into drum 1 by the fixed i.e. nonrotating conduits 12 and 13. The mercury is here at the entrance potential. One can follow the progression of rotation best by looking at openings 14 and 15. After a rotation by about 90 the system arrives at the position shown in FIGURE 3b where the contents, a pool at the lowest region of cylinder 1, are discharged and emptied into cylinder 2, the mercury being still at the entrance potential.

After reaching the position shown in FIGURE 3c (about 45 from that of FIGURE 3b) the mercury pool in drum 1 is still at the entrance potential but it is now completely separated from the mercury pool in cylinder 2, the latter being at an intermediate and indefinite potential.

In FIGURE 3d the mercury pool in drum 2 is completely discharged into housing 3 where it is at the exit potential. It is apparent that the assumption of a new potential of the mercury when pouring from drum 2 into housing 3 is a completely electrostatic process involving for all practical purposes no energy.

As can be easily seen, the functioning of the apparatus is simple, and always certain.

It is obvious that the apparatus described above represents only one form of this invention and modifications thereof are readily within the realm of the invention. Thus, in FIGURE 4 is shown an arrangement wherein the two drums 1 and 2 are integral with each other and they have the same hollow shaft 4. In such a case it is necessary to insulate the drum-s from the remaining parts of the apparatus by an inner lining, for example, a coating of ebonite. In FIGURE 4, the different reference numerals have the same significance as in FIGURE 1 in general.

Reference numeral 20, however, represents an additional insulating support for the conduits 12 and 13; 21 is an insulating connection between the housing 3 and the roller bearing 6 which roller bearing is supported by a support 22. The roller bearing is covered by an ebonited member 23. There is a sealing ring 24 to prevent mercury from creeping along the shaft 4. Further protection is afforded by a cap 25.

It will be apparent that drum assembly 124 is (1) normally insulated from housing 3, and (2) normally in sulated from conduits 12 and 13. For purpose of describing the operation reference can be made again to FIG- URES 3a to 3d. In the situation of FIGURE 3a the mercury electrically connects only the mercury pool in drum 1 to conduits 12, 13 due to insulation of the drums; no connection is present to housing 3.

In the situation of FIGURE 31) there is electrical interconnection between the pools in drums 1 and 2. In FIGURE 30 no electrical connection between the pools in drums 1 and 2 is present so that the pool in drum 1 is kept at the potential of conduits 12 and 13 whereas the pool in drum 2 is separated therefrom and at an intermediate potential.

According to FIGURE 3d, there now is an electrical connection between the pool in drum 2 and housing 3, outlet 17 etc., while no connection can be found between the newly formed pool in drum 1. One can see that pool interconnection is possible only (FIG. 3b) when opening 15 is on top so that surely no mercury discharge occurs anymore between the pool in drum 2, if any, into housing 3, while the pools are interconnected.

FIGURE shows another modification in which there i is a disc 26 between drums 1 and 2 to prevent gradual creeping of the mercury on the insulated walls. Otherwise the design of the device of FIGURE 5 follows that of FIGURE 4.

The invention is not limited to the embodiments described above but all changes and modifications thereof not constituting departures from the spirit and scope of the invention are intended to be covered by the following claims:

What is claimed is:

1. In an apparatus for the electrolysis of aqueous solutions of alkali metal halides in cells having movable cathode mercury and with provision for separation of the amalgam formed in such cells, an arrangement for interrupting periodically the flow of mercury and/ or amalgam between the cells and the separating element comprising: a housing; a first drum having hollow shaft means and being journaled therewith in said housing and being electrically insulated therefrom, said first drum having at its circumferential mantle a discharge outlet; a second drum coaxially disposed in said first drum and having a liquid receiving space insulated from said first drum, there being means for positively interconnecting said first and second drum; means for driving said drums to rotate in unison; said second drum having a discharge outlet angularly displaced from the discharge outlet of said first drum, conduit means in said hollow shaft electrically insulated from said first and said second drums for discharging liquid such as mercury and/or amalgam into said second drum to such an extent that any outpour of liquid from said first drum through its outlet and into said housing is completely interrupted during any outpour of liquid from said second drum through its outlet into said first drum; means defining a degassing outlet of said housing; and means defining a liquid discharge outlet from said housing.

2. In an apparatus for the electrolysis of aqueous solutions of alkali metal halides in cells having movable cathode mercury and with provision for separation of the amalgam formed in such cells, an arrangement for interrupting periodically the flow of mercury and/or amalgam between the cells and the separating element comprising: a housing; a first drum having hollow shaft means and being journaled therewith in said housing and being electrically insulated therefrom, said first drum having at its circumferential mantle a discharge outlet; 21 second drum coaxially disposed in said first drum, electrically insulated therefrom and having a hollow shaft received by the hollow shaft of said first drum; means including electrically insulating means for positively interconnecting said first and second drums for common rotation; means for driving said drums to rotate in unison; conduit means traversing said hollow shaft of said second drum for discharging liquid such as mercury and/ or amalgam into the interior of said second drum, said second drum having a discharge outlet angularly displaced from the discharge outlet of said first drum to such an extent that any outpour of liquid from said first drum through its outlet and into said housing is completely interrupted during any outpour of liquid from said second drum through its outlet into said first drum; means defining a degassing outlet of said housing; and means defining a liquid discharge outlet from said housing.

3. In an apparatus for the electrolysis of aqueous solutions of alkali metal halides in cells having movable cathode mercury and with provision for separation of the amalgam formed in such cells, an arrangement for interrupting periodically the flow of mercury and/ or amalgam between the cells and the separating element comprising: a housing; a first drum having hollow shaft means and being journaled therewith in said housing and being electrically insulated therefrom, said first drum having at its circumferential mantle in a discharge outlet; a second drum coaxially disposed in said first drum and integral therewith, each drum having an electrically insulating inner lining; means for driving said drums to rotate in unison; conduit means in said hollow shaft and being electrically insulated from said first and said second drums for discharging liquid such as mercury and/ or amalgam into said second drum, said second drum having a discharge outlet angularly displaced from the discharge outlet of said first drum to such an extent that any outpour of liquid from said first drum through its outlet and into said housing is completely interrupted during any outpour of liquid from said second drum through its outlet into said first drum; means defining a degassing outlet of said housing; and means defining a liquid discharge outlet from said housing.

4. In an apparatus for the electrolysis of aqueous solutions of alkali metal halides in cells having movable cathode mercury and with provision for separation of the amalgam formed in such cells, an arrangement for interrupting periodically the flow of mercury and/or amalgam between the cells and the separating element comprising: a housing; a plurality of coaXially disposed drums emboxed in each other, each drum having a'liquid receiving space insulated from that of any other drum; each drum having a liquid discharge opening angularly displaced from that of any adjoining drum; conduit means for discharging liquid such as mercury and/or amalgam into the innermost drum; means defining a degassing outlet of said housing; and means defining a liquid discharge outlet from said housing.

5. In an apparatus for the electrolysis of aqueous solutions of alkali metal halides in cells having movable cathode mercury and with provision for separation of the amalgam formed in such cells, an arrangement for interrupting periodically the flow of mercury and/ or amalgam between the cells and the separating element comprising: a housing; a first drum having hollow shaft means and being journaled therewith in said housing and being electrically insulated therefrom, said first drum having at its circumferential mantle a discharge outlet; a second drum coaxially disposed in said first drum and having a liquid receiving space insulated from said first drum, there being means for positively interconnecting said first and second drum; means for driving said drums to rotate in unison; first conduit means in said hollow shaft electrically insulated from said first and said second drums for discharging liquid such as mercury and/or amalgam into said second drum; second conduit means for discharging an additional liquid into said second drum; said second drum having a discharge outlet angularly displaced from the discharge outlet of said first drum to such an extent that any outpour of liquid from said first drum through its outlet and into said housing is completely interrupted during any outpour of liquid from said second drum through its outlet into said first drum; means defining a degassing outlet of said housing; and means defining a liquid discharge outlet from said housmg.

References Cited UNITED STATES PATENTS 2,849,524 8/1958 Matsuo et al. 20'4-220 JOHN H. MACK, Primary Examiner.

E. ZAGARELLA, Assistant Examiner. 

1. IN AN APPARATUS FOR THE ELECTROLYSIS OF AQUEOUS SOLUTIONS OF ALKALI METAL HALIDES IN CELLS HAVING MOVABLE CATHODE MERCURY AND WITH PROVISIONS FOR SEPARATION OF THE AMALGAM FORCED IN SUCH CELLS, AN ARRANGEMENT FOR INTERRUPTING PERIODICALLY THE FLOW OF MERCURY AND/OR AMALGAM BETWEEN THE CELLS AND THE SEPARATING ELEMENT COMPRISING: A HOUSING, A FIRST DRUM HAVING HOLLOW SHAFT MEANS AND BEING JOURNALED THEREWITH IN SAID HOUSING AND BEING ELECTRICALLY INSULATED THEREFROM, SAID FIRST DRUM HAVING AT ITS CIRCUMFERENTIAL MANTLE A DISCHARGE OUTLET; A SECOND DRUM COAXIALLY DISPOSED IN SAID FRIST DRUM AND HAVING A LIQUID RECEIVING SPACE INSULATED FROM SAID FIRST DRUM, THERE BEING MEANS FOR POSITEBELY INTERCONNECTING SAID FIRST AND SECOND DRUM; MEANS FOR DRIVING SAID DRUMS TO ROTATE IN UNISON; SAID SECOND DRUM HAVING A DISCHARGE OUTLET ANGULARLY DISPLACED FROM THE DISCHARGE OUTLET OF SAID FIRST DRUM, CONDUIT MEANS IN SAID HOLLOW SHAFT ELECTRICALLY INSULATED FROM SAID DRIST AND SAID SECOND DRUMS FOR DISCHARGING LIQUID SUCH AS MERCURY AND/OR AMALGAM INTO SAID SECOND DRUM TO SUCH AN EXTENT THAT ANY OUTPUT OF LIQUID FROM SAID FIRST DRUM THROUGH ITS OUTLET AND INTO SAID HOUSING IS COMPELTELY INTERRRUPTED DURING ANY OUTPOUR OF LIQUID FROM SAID SECOND DRUM THROUGH ITS OUTLET INTO SAID FIRST DRUM; MEANS DEFINING A DEGASSING OUTLET OF SAID HOUSING; AND MEANS DEFINING A LIQUID DISCHARGE OUTLET FROM SAID HOUSING. 